This laboratory is currently engaged in determining the role of outer membrane proteins in the pathogenesis of Hemophilus influenzae, an organism responsible for serious infections including meningitis. We have been successful in isolating and characterizing the outer membrane of H. influenzae type b. In addition, we have obtained evidence that rabbits exposed to whole bacteria make antibodies to the outer membrane proteins of H. influenzae. We propose to determine if humans also make antibodies to these proteins and to identify the particular proteins which are immunogenic. The final goal is to assess the feasibility of using such proteins as a vaccine.